Pollen allergy (hay fever)

Pollen allergy (hay fever) is the most common allergic disease in our part of the world. Typical symptoms are sneezing attacks, runny nose and streaming eyes.

Sufferers react to one or more types of pollen, most often to grass. It rarely appears before the third year of life. As a rule, the symptoms do not start until school age. The purpose of pollen is the fertilisation of plants. A distinction is made between insect- and wind-pollinated plants and it is the latter that trigger pollen allergies. Out of around 3500 plants in Switzerland, only about 20 have any significance for pollen allergy sufferers.

Causes and triggers of pollen allergy

Pollen allergy (hay fever) is a reaction to one or more types of pollen; the predisposition to pollen allergy is often inherited. It involves the immune system reacting to the proteins of pollen which in themselves are harmless. As a result of inhalation or direct contact with pollen, histamine is released in allergy sufferers which leads to inflammation of the conjunctiva of the eyes and the lining of the nose.

These are the three main groups of plant that trigger a pollen allergy:

Trees: hazel, alder, ash, birch, hornbeam, oak

Grasses: for example, timothy, cocksfoot, English ryegrass

Weeds: mugwort, ragweed (Ambrosia artemisiifolia)

Symptoms of pollen allergy

The following symptoms may occur: sneezing attacks, runny nose (rhinitis), blocked nose, difficulty breathing through the nose, itchy and streaming eyes (conjunctivitis), itching in the palate, nose and ears, hoarseness, irritation of the throat. A build-up of mucus in the paranasal sinuses can cause headaches and jaw pains. Pollen allergy that is left untreated for a lengthy period of time can develop into allergic asthma, which is known as progression.

Diagnosis and differential diagnosis

The diagnosis is based on thorough history-taking with the aid of skin and blood tests. Similar symptoms can occur in cases of house dust mite or mould allergy. Differences can mainly be identified in the place and time of onset of the symptoms. This is why it is worth observing the symptoms accurately.

Therapy and treatment

Various medicines in the form of nasal sprays, eye drops or tablets/drops can be used to treat the symptoms of pollen allergy. The most important groups of active substances include antihistamines, corticosteroids (cortisone drugs), leukotriene antagonists and mast cell stabilizers. More information about the active substance groups and their mechanisms of action can be found on the page «Pollen allergy treatment». Desensitization/specific immunotherapy (SIT) is so far the only possible way of causally treating the symptoms of pollen allergy. It calls for investigation by an allergy specialist (allergologist). Certain therapies from complementary medicine can also relieve the symptoms successfully. Which form of treatment is suitable should be discussed with the relevant therapist.

Facts and figures

In Switzerland around 1.2 million people, roughly 20% of the population, are affected. The flower of a single blade of grass contains around 4 million flower pollen grains. Conifers are among the flower pollens that do not trigger any allergy. Visible as a yellow dust-fall in springtime, at most they cause irritation of the conjunctiva.